Drive for printing rollers of printing machines



Jan. 20, 1959 H. P. BOHME DRIVE FOR PRINTING ROLLERS OF PRINTING MACHINES Filed April 21, 1954 IN VEN TOR. flaws .3 671mg Unite rates naive Fon rnmrmo ROLLERS or rmNriNo MAcmNEs Hans P. Biihrne, Krefeld, Germany, assignor to Job. Kleinevvefers Sohne, Krefeld, Germany The present invention relates to a drive for the printing rollers of printing machines, and more particularly to printing machines with a rapport mechanism.

With heretofore known printing machines employing printing rollers, and particularly with such printing machines in which the printing rollers are journalled in antifriction bearings, it is a well-known fact that under certain working conditions, individual printing rollers have the tendency to run' ahead of other printing rollers with which they are supposed to work in mutual dependency' (in rapport), and thus fall out of step. In other'words the force-locked mutual engagement of the teeth of the rapport gears is not maintained as a result or which the rollers. swing back and forth within the always present backlash of the teeth. In order to overcome this drawback, it has heretofore been the customary procedure to brake the rollers or to step the circumference of the printing rollers in order in this way always to maintain the teeth of the rapport gear in contact with the cooperatingteeth of the adjacent gear.

The first mentioned procedure has the drawback that braking losses occur which result in mechanical wear of the braking elements (lateral rapport rings). With modern roller printing machines in which the rollers are journalled in anti-friction bearings, it is not possible to brake the printing rollers nor is it desirable to brake the printing rollers for high printing speeds. With the second mentioned procedure, the printing rollers can be employed only in a certain definite seq-ttence' which fact is a considerable handicap with regard to the composing of different colors.

Itis, therefore, an object of the present invention to provide an arrangement which will. overcome the above mentioned drawbacks.

It is another object of this invention to provide a drivefor printing machines adapted to print on fabrics, which will compensate for the running ahead of one more printing rollers.

It is still another object of this invention to provide a drive for printing machines adapted to print upon fabrics, in which the force-locked mutual engagement of the teeth of cooperating gears will be reliably assured.

These and other objects and advantages of the inven tion will appear more clearly from the following specification in connection with the accompanying drawing showing one embodiment of the invention.

General arrangement The above mentioned drawbacks inherent to heretofore known drives for printing machines adapted to print upon fabrics and provided with mechanical rapport or synchronizing means between the driven printing rollers, have'been overcome according to the present invention by'an arrangement in which the shaft of each driven printing roller ora drive wheel rigidly connected to said shaft is continuously operatively connected with a separately variable drive motor through a first transmission 2,869,459 Patented Jan. 20, 19 59 'ice and with the central wheel of the rapport or synchroniz ing mechanism through a second transmission. It is, of course, understood that the mechanical rapport or syn" chronizing mechanism may be of various types. Thus, the adjustment of the rapport or synchronism may be effected by mechanical elements such as worm wheel drive, differential drive and planetary gear system in a manner known per se. 7

With such an arrangement, the disturbing running of one or more printing rollers ahead of the rapport is compensated for by varying the field of the respective motor with regard to a lower or higher speed of rotation. In this way the force locked engagement of the teeth which is desirable in order precisely to maintain the rapport or synchronism is assured in a reliable manner. In this connection it is irrelevant whether the swinging oroscillating printing roller is speeded up or is retarded. The respective motor will conformingly be loaded either more or less.

Since with modern high output roller printing machines it is customary in order to relieve the printing cloth, to provide primarily multi=motor drives with separate drive for the drying device, it is preferable to employ a direct current multi-motor drive for the drive of the printing rollers. The individual motors with controlled armature voltage allow a variation of the printing speed and additionally have their field controlled. in this connection the field regulators or controlling means for the driving motors serve primarily to compensate the backlash of the teeth when such backlash occurs after the drive has been in use for a longer period of time.

Structural arrangement Referring now to the drawing in detail, the machine frame comprises the two lateral supports 1 and 2 These supports are provided with bearings 3 and 4 in which is journalled a press cylinder 5. The press cylinder 5 cooperates with the printing rollers 6. While the drawing shows only two printing rollers, it is, of course, understood thatalso more than two printing rollers may be provided and evenly arranged along the circumference of the press cylinder 5.

In order to allow the employment of rollers with different diameter while still producing the desired pressure to be exertedby the rollers, the bearings 7 for the printing rollers are arranged so that they can be radially displaced together with the gears 12 and rollers 6. To this end, each bearing 7 is journalled in a substantially radial slot 7a and provided with lateral plates 2b which laterally engage supports 1 and 2 respectively and thus hold the bearing 7 in slot 70. A spindle 8 extends through a spindle bearing 8a mounted in said supports 1 and 2 respectively and laterally engaged by plates 8b which are connected to the respective supports 1 and 2 adjacent thereto. The drive and the remaining portion of the gear transmission comprising gears 11, 13 and 18 and the parts cooperating therewith mounted on a plate 31 are so arranged thatthey' can be turned together withplate 31 a'oouta bearing 3 2'for said plate 31 and thus about the central wheel 19 until the proper backlash between the gears 11 and 12 has been obtained. The elec tric motors 9 individually drive the respective printing rollers 6 through a transmission 10 .and the two gears 11 and 12. The gear 11 simultaneously rotates a further gear 13 which latter through a shaft 14 is conse by rotating the casing 20 of the planetary gearing 16. shaft 14 being journalled in a frame 31:: connected to plate 31. The other sun wheel 30 is drivingly connected with the central Wheel 19 through a hollow shaft 17 and a gear 18. The two planetary gears are designated with the reference numeral 29. The adjustment of the rapport or synchronism is effected in a manner known per se by rotating the casing 20 of the planetary gearing 16. The casing 20 is driven by the adjusting motor 24 through the intervention of a gearing 21, a worm wheel 22 and a belt 23. Thus, while the motors 9 represent the driving motors proper for driving the printing rollers 6 as well as the central wheel or gear 19 and thereby the press cylinder 5, the adjusting motors 24 are adapted through gear 19to vary the angular relative position between the cylinder and the printingrollers 6. The armature voltage of the motors 9 is controlled by a variable direct current source which latter is controlled by a rheostat 25 which may also be replaced by any other appropriate controlling device. The field voltage of the motors 9 is controlled by a rheostat 26 or any other appropriate controlling device. Switches 27 are provided for selectively switching the motors 9 on and off. The device furthermore comprises ampere meters 28 for checking the currents. The switches 27, controlling devices 25 and 26 and the ampere meters 28 are preferably mounted on a control board common to them as indicated in the drawing by dot-dash lines.

The control of the field of the direct current motors 9 makes it possible in a fine sensitive manner to counteract the disturbing impulses which cause the printing rollers 6 to oscillate or swing. This arrangement merely brings about a certain distribution of the driving output over the individual printing roller 6 so that normally no additional power is required for the driving of the machine.

The individual motor transmissions are preferably mounted on the machine frame which results in a considerable saving in space over the space required with heretofore known arrangements employing a central drive. Preferably the individual motor drives are rotatable or tiltable.

It is, of course, understood that the present invention is, by no means, limited to the specific arrangement shown in the drawing but also comprises any modification within the scope of the appended claims.

What I claim is:

1. In a drive for printing machines for printing upon fabrics, which are provided with a mechanical rapport mechanism for maintaining a desired operative relationship between the driven printing rollers, the combination of: a first rotatable printing roller, a second rotatable printing roller, first transmission means drivingly connected to said first printing roller, second transmission means drivingly connected to said second printing roller, 11 pair of individually variable drive motors respectively drivingly connected with said first and said second transmission means, a rotatable cylinder for supporting the fabric to be printed on, a central gear drivingly connected to said cylinder, a pair of additional transmission means respectively drivingly connecting said central gear with each of said individually variable drive motors and thereby also with said first and second printing rollers, and adjusting motor means independent of said individually variable drive motors and drivingly connected with said central gear and thereby also with said rotatable cylinder and said additional transmission means for varying the position of said central gear and thereby of said rotatable cylinder relative to said printing rollers.

2. An arrangement according to claim 1, in which each of said additional transmission means includes a differential gear transmission.

3. In a drive for printing machines for printing upon fabrics, which are provided with a mechanical rapport mechanism for maintaining a desired operative relationship between the driven printing rollers, the combination of: a first rotatable printing roller, a second rotatable printing roller, first transmission means drivingly connected to said first printing roller, second transmission means drivingly connected'to said second printing roller, a pair of individually variable direct current electric ,4 motors respectively drivingly connected with said first and second transmission means, a rotatable cylinder for supporting the fabric to be printed on, a central'gear drivingly connected to said cylinder, a pair of additional transmission means respectively drivingly connecting said central gear with each of said individually variable drive motors and thereby also with said first and second printing rollers, and adjusting motor means independent of said individually variable drive motors and drivingly connected with said central gear and thereby also with said rotatable cylinder and said additional transmission means for varying the position of said central gear and thereby of said rotatable cylinder relative to said printing rollers.

4. An arrangement according to claim 3, in which each of said direct current electric motors has associated therewith a field regulator for respectively controlling the armature voltage of the respective electric motor.

5. An arrangement according to claim 3, which comprises a switch board and control means mounted on said switch board, said control means including instruments for checking the current passing to said electric motors and also including switch means for selectively interrupting the supply of current to either one or both of said motors.

6. In a drive for printing machines for printing upon fabrics, which are provided with a mechanical rapport mechanism for maintaining a desired operative relationship between the driven printing rollers, the combination of: frame means, a rotatable cylinder journalled in said frame means, a first printing roller arranged adjacent said cylinder and supported by said frame means, a second printing roller arranged adjacent said cylinder in spaced relationship to said first printing roller, first transmission means drivingly connected to said first printing roller,

r second transmission means drivingly connected to said second printing roller, two individually variable drive motors respectively drivingly connected with said first and said second transmission means and arranged directly adjacent said frame means, a central gear coaxially arranged with and drivingly connected to said cylinder and rotatably supported by said frame means, a pair of additional transmission means respectively interposed between and drivingly interconnecting said central gear and each of said individually variable drive motors thereby drivingly connecting said central gear also with each of said first and second printing rollers, and adjusting motor means independent of said individually variable drive motors and drivingly connected with said central gear and thereby also with said rotatable cylinder and said additional transmission means for varying the position of said central gear and thereby of said rotatable cylinder relative to said printing rollers.

7. In a drive for printing machines for printing upon fabrics, which are provided with a mechanical rapport mechanism for maintaining a desired operative relationship between the driven printing rollers, the combination of: frame means, a rotatable cylinder journalled in said frame means, a first printing roller arranged adjacent said cylinder and supported by said frame means, a second printing roller arranged adjacent said cylinder in spaced relationship to said first printing roller, first transmission means drivingly connected to said first printing roller, second transmission means drivingly connected to said second printing roller, two individually variable drive motors respectively drivingly connected to said first and said second transmission means, a central gear coaxially arranged with and drivingly connected to said cylinder, bearing means supported by said frame means for rotatably supporting said central gear, third transmission means drivingly connecting said first transmission means with said central gear, fourth transmission means drivingly connecting said second transmission means with said central gear, tiltable means carrying said third and fourth transmission means and parts of said second and first transmission means and being tiltably supported by References Cited in the file of this patent UNITED STATES PATENTS Luttenauer July 17, Bojanower et al. Oct. 2, Bornmelaer Apr. 7, Deck May 12, 

